This project is concerned with studies of the genetic diversity of Trypanosoma cruzi and its implications to the epidemiology and diagnosis of Chagas' disease. Emphasis during the year has centered upon: 1) Completion of the analysis of the infection of inbred mice with T. cruzi clones, 2) Analysis and modeling of the population dynamics of T. cruzi clone mixtures, 3) Development of mutant T. cruzi clones, 4) Pulse gel electrophoretic analyses of T. cruzi clones, 5) Utilization of PARACYT-1, the LPD flow cytometer, to study the DNA synthetic cycle of Giardia lamblia and Candida spp. and 6) Completion of a Medlars-based bibliography on Chagas' disease.